#include<iostream>
#include<vector>
#include<string>
using namespace std;

class Solution {
public:

    bool isBadVersion(int n) {
        return false;
    }

    int firstBadVersion(int n) {
        int left = 1, right = n;
        while (left < right) {
            int mid = left + (right - left) / 2;
            if (isBadVersion(mid)) {
                right = mid;
            }
            else left = mid + 1;
        }
        return left;
    }
};

int main() {

}